
Issued September 9, 1912. 

U. S. DEPARTMENT OF AGRICULTURE, 

BUREAU OF ANIMAL INDUSTRY.— Bulletin 152. 

A. D. MELVIN, CiiiEi^ or Bureau. 



B^*2 



STUDIES ON THE BIOLOGY OF 
THE TEXAS-FEVER TICK. 



(SUPPLEMENTARY REPORT.). 



BY 



H. W. GRAYBILL, D. V. M., 

Assistant Zoologist, Zoological Division, 
AND 

W. M. LEWALLEN, 

Agent in Tick Eradication, Bureau of Anivial Industry. 




WASHINGTON: 

GOVERNMENT PRINTING OFFICE. 

1912. 



-ti^. 




Glass SF 5 33 

Book TVs- G^ ^ ^ 



I^siu'il September 9, 1912. 

U. S. DEPARTMENT OF AGRICULTURE, 

BUREAU OF ANIMAL INDUSTRY.— Bulletin 152. 

A. D. MELVIN, Chief of Bureau. 



STUDIES ON THE BIOLOGY OF 
THE TEXAS-FEVER TICK. uui> 



(SUPPLEMENTARY REPORT.) ., - —- 



BY 



H. W. GRAYBILL, D. V. M., 

Assistant Zoologist, Zoological Division, 



AND 



W. M. LEWALLEN, 

Agent in Tick Eradication, Bureau of Aiiimal hidustry. 




WASHINGTON: 

GOVERNMENT PRINTING OFFICE. 

1912. 



^^ 



6<^^^^ 



< 






BUREAU OF ANIMAL INDUSTRY. 



Chief: A. D. Melvin. 

Assistant Chief: A. M. Farrington. 

Chief Clerk: Charles C. Carroll. 

Animal Husbandry Division: George M. Kommel, chief. 

Biochemic Division: M. Dorset, chief. 

Dairy Division: B. H. Rawl, chief. 

Field Inspection Division: R. A. Ramsay, chief. 

Meat Inspection Division: Rice P. StjSDDOM, chief. 

Pathological Division: John R. Mohler, chief. 

Quarantine Division: Richard W. Hickman, chief. 

Zoological Division: B. H. Ransom, chief. 

Experiment Station: E. C. Schroeder, superintendent. 

Editor: James M. Pickens. 

ZOOLOGICAL DIVISION. 

Chief: B. H. Ransom. 

Assistant Zoologists: Albert IIassall, Harry W. Graybill, Maurice C. Hall, 
and Howard Crawley. 

JumorZooZo^isf; WiNTHROP D. Foster. ' 



additional copies of this publication 
-t\- may be procured from the Superintend- 
ent OF Documents, Government Printing 
OflBco Washington, D. C, at 5 cents per copy. 



LETTER OF TRANSMITTAL. 



L^. S. Department of Agriculture, 

Bureau of Animal Industry, 
Washington, D. C, April 25, 1912. 
Sir: In Bulletin 130 of this bureau there were reported the results 
of one year's investigations of the biology of the Texas-fever tick 
which were carried on during 1907 and 1908 at Auburn, Ala., by 
cooperation between the Alabama Polytechnic Institute and this 
bureau. The work was continued for another year, and I have the 
honor to transmit herewith a supplementary report by Dr. H. W. 
Graybill and Mr. W. M. Lewallen, giving the results of the second 
year's experiments (1908-9). As this information has a bearing on 
the cooperative work now being carried on by the bureau and the 
authorities of certain States for the eradication of the cattle tick, I 
recommend its publication as a bulletin of this bureau. 
Respectfully, 

A. D. Melvin, 
Chief of Bureau , 
Hon. James Wilson, 

Secretary of Agriculture. 



CONTENTS. 



Page. 

Introduetion ^ 5 

Methods of study " 5 

Preoviposition period 6 

O viposition period 6 

Incubation period 7 

Hatching period 8 

Longevity period 8 

Entire time of nonparasitic development 9 

Number of eggs laid and percentage hatched 10 

Comparison of results of indoor and outdoor experiments 10 

Appendix 13 



STUDIES ON THE BIOLOGY OF THE TEXAS-FEVER TICK. 

(SUPPLEMENTARY REPORT.) 



INTRODUCTION. 

During 1907-8 the Zoological Division of tlie Bureau of Animal 
Industry conducted a year's experiments on the life history of the 
Texas-fever tick at Auburn, Ala., in cooperation with the veterinary 
department of the Alabama Polyteclmic Listitute. The results 
obtamed during the course of those investigations have been pub- 
lished in Bulletin 130 of the Bureau of Animal Industry. The work 
was continued for another year (1908-9) along the same but some- 
what less extensive lines. Mr. W. M. Lewallen, who assisted in the 
first year's work, had charge of the experiments during the second 
year. 

The second year's work was undertaken for the purpose of obtain- 
ing additional data on the nonparasitic periods in the life history of 
the tick, and to determine what variations might take place in the 
duration of these as a result of yearly variations in weather contUtions. 

METHODS OF STUDY. 

The methods of study employed were the same as those used the 
first year. The indoor experiments were conducted by the use of 
incubation tubes, and these were checked by outdoor experiments 
conducted in field plots representing natural conditions. The incu- 
bation tubes used were the vertical type provided with a glass tube 
inserted into the bottom for the puqDose of supplying the sand with 
moisture, shown in figure 1, Bulletin 130, Bureau of Animal Industry. 
The field plots were the same as those used in the first year's work 
(fig. 3, Bulletin 130), being 2 feet square. They were protected from 
the intrusion of small animals by means of a wire-netting fence. 

In the indoor experiments the ticks were handled the same as during 
the first year. Four engorged ticks were collected at the beginning 
of each month, and each was j)laced in a dish by itself, where it 
remained until oviposition was completed. At the end of every 24 
hours the eggs were removed from each tick, counted, and placed in 
an incubation tube marked with the number assigned the tick and 
the date the eggs were removed. The dates when the eggs in each 
tube began and completed hatching, and when the first and last larvae 

5 



6 



BIOLOGY OF THE TEXAS-FEVER TICK. 



died, were recorded, and finally the per cent of eggs that liatched was 
determined. The indoor experiments were conducted in an unheated 
room, the windows of which were constantly open. 

In the outdoor experiments two sets of plots were run, one located 
in a place shaded a part of the day and the other in the sun. In each 
plot 10 engorged females were placed. 

PREOVIPOSITION PERIOD. 

The minimum preoviposition period noted was 2 days, which 
occurred in the case of ticks collected in August. Ticks collected in 
August the first year had a minimum period of 2 days, but the mini- 
mum for the year (1 day) was observed in the case of a tick collected 
in April. The maximum period (29 days) was exhibited by ticks 
collected December 2, and the maximum for the first year (98 days) 
was observed in the case of a tick collected November 30. 

From the table (last column) it will be noted that the average pre- 
oviposition periods increase month by month from the minimum to 
the' maximum, and then decrease again to the minimum. A similar 
increase and decrease were also shown in the case of averages for the 
first year's experiments in the horizontal tubes, but in the case of the 
ticks used for the vertical-tube experiments the averages for April 
and June were greater than for March. 

Preoviposition period — Range and average length of periods. 



Date ticks were 
collected. 


Number 
of ticks. 


Range of 
preovi- 
position 
periods. 


Average 
of preovi- 
position 
periods. 


Date ticks were 
collected. 


Number 
of ticks. 


Rangeof 
preovi- 
position 
periods. 


Average 
of preovi- 
position 
periods. 


190S. 
Augusts 


4 

4 
4 

4 
4 


• Bays. 

2 to 4 

3 to 5 
5 to 11 
7 to 9 

17 to 29 


Days. 

4 

8!3 
25.5 


i 1909. 

January 1 

February 4 




Days. 
22 to 24 
18 to 20- 
9 to 16 
9 to 10 
3 


^%- 


September 1 

October 1 


19.3 


November 2 


April 2 


r 9 8 















OVIPOSITION PERIOD. 

The longest oviposition period noted was 82 days, observed in the 
case of a tick which began ovipositing in January. A tick in the first 
year's, experiments which began to lay eggs in January had an ovi- 
position period of 91 days, but the longest period was exhibited by a 
tick which began ovipositing in November and continued to lay eggs 
for 152 days. The second year the shortest period (7 days), as weU 
as the longest, occurred in January. The tick giving this period, 
however, deposited only 305 eggs, an exceptionally small number. 
The shortest period the first year was 3 days, and this occurred in June. 
The average oviposition periods for the first year increased month by 
month from a minimum in June to a maximum in November, and 



INCUBATIOX PERIOD. 7 

gradually decreased again in the succeeding months. During the 
second year the same tendency was shown, the periods increasing 
from a minimum in August to a maximum in November, and then, 
following a sudden decrease for December, there was an increase for 
January and February, after wliich the decrease was regular for the 
remauiuig months. 

Oviposition period — Range and average length of periods. 



Month oviposi- 
tion began. 


Number 
of ticks. 


Range 
of ovi- 
position 
periods. 


Average 
of ovi- 
position 
periods. 


Month oviposi- 
tion began. 


Number 
of ticks. 


Range 
of ovi- 
position 
periods. 


Average 
of ovi- 
position 
periods. 


1908. 
August 


4 


Days. 
13 to 15 
9 to 18 
13 to 35 
56 to 63 
30 to 42 

7 to 82 


Days. 
14.3 
14.8 
25.3 
59.5 
34.5 

45.8 


1909. 

February 

March 




Days. 
37 to 59 
22 to 42 
26 to 32 
19 to 27 

11 to 19 

12 to 17 


Days. 
46.8 
33.3 


September 




April 


November 


M^y 


23 8 


December 


June 


15.8 




July 


1909. 











INCUBATION PERIOD. 



The range of the incubation periods of the lots of eggs laid by each 
tick is given in the table in the Appendix. The range of the period 
for the second year was 18 to 176 days, as compared with 19 to 188 
days for the first year. In the table below only the periods from the 
time the eggs were deposited until the first eggs hatched in each lot 
have been used, and these are referred to for convenience as the mini- 
mum incubation periods. The periods to the hatching of the last 
eggs in each lot have been included in the table in the Appendix. 
The longest minimum incubation period for both the first and the 
second year occurred in the case of lots of eggs deposited during the 
month of October, being 173 days for the second year and ISO days 
for the first year. The shortest period for the second year was 18 
days and was observed in the case of lots of eggs deposited during 
the month of June, wliile the lots deposited during the same month 
of the first year gave a minimum period of 22 days. The shortest 
period for the first year (19 days) was furnished by lots of eggs depos- 
ited during the months of July and August. 

By comparing the averages in the table below it will be observed 
that they increase from August to October and decrease for the re- 
maining months, except in the case of the average for July, which 
shows a slight increase. In case of the averages for the first year it 
is noted that they increase for the months of August to October and 
decrease for the remaining months without interruption. 



8 BIOLOGY OP THE TEXAS-FEVER TICK. 

Minimum incubation 'period — liange and average length of periods. 



Month eggs de- 
posited. 


Number 
of lots. 


Range of 
periods. 


Average 
of periods. 


Month egcs de- 
posited. 


Nunlber 
of lots. 


Range of 
periods. 


Average 
of periods. 


1908. 
August 


52 
49 
49 
66 
21 

70 


Days. 
20 to 30 
32 to 70 
141 to 173 
151 to 171 
139 to 15S 

103 to 141 


Bays. 
23.1 
44.8 
158. 7 
157. 5 
150.3 

121. G 


1909. 

February 

March 


48 
170 
141 
90 
47 
51 


Days. 

82 to 107 
5Sto 90 
38 to 65 
26 to 39 
IS to 26 
22 to 27 


Days. 
95 5 








April 




November 


Mav 


30 6 










July 


94 5 


19:9. 











HATCHING PERIOD. 

The maximum hatching period for the second year was 52 days 
and for the first year 49 days, and in the case of both years tliis 
period belonged to a tick whose eggs began to hatch during the 
month of October. The shortest hatcliing period for the second year 
was 6 days and occurred in the case of a tick whose eggs began to 
hatch in JMay, wliile for the first year the minimum period for the 
same month was 9 days. The shortest period during the first year 
(4 days) fell to the month of July, It is noted by referring to the 
averages in the table below that those for October and February are 
the same, and for the remaining months, with the exception of the 
break shown by May, there is a decrease, month by month, of the 
averages. In the first year's work the averages increased from that 
for July to the maximum, which is for the month of October, and 
decreased for the remaining months, except for a slight increase for 
the month of June. 

Hatching period — Range and average length of periods. 



Month hatching 
began. 


Number 
of ticks. 


Range of 
hatching 
periods. 


Average 
of hatch- 
ing 
periods. 


Month hatching 
began. 


Number 
of ticks. 


Range of 
hatching 
periods. 


Average 
of hatch- 
' ing 

periods. 


1908. 
August 


4 

4 

1 


, Days. ^ 
17 to 27 
47 to 52 

50 


Days. 

21.5 
50 

SO' 


1909. 
March 


4 

20 
4 
8 


Days. 
33 to 46 
IS to 21 
6 to 21 
12 to IS 
11 to 21 


Days. 
39 5 


October 




19.3 




May 


13.8 


1909. 




16 


Pebruary 


July 


14 5 







LONGEVITY PERIOD. 

The longest and shortest longevity periods obtained for the lots 
of larvae belonging to each tick are given in the table in the Appendix. 
The time to the death of the first larvae in each lot is referred to 
in the table below as 'the minimum longevity period and that to the 
death of the last larvae as the maximum longevity period. The 
longest maximum longevity period for the second year was 249 
days, as compared with 234 days for the first year, and both 



TIME OF XONPARASITIC DEVELOPMENT. 



9 



occurred in the case of lots of eggs which began to hatch (hn-ing 
the month of October. In referring to the averages it will be 
noted that there is no regular mcrease and decrease to and from 
the maximum, and the same was noted in the case of the first 
year's experiments. This is no doubt due to the fact that tem- 
perature, while it plays some part, is not a controllmg factor in 
the longevity of larvje as it is in the case of the preoviposition, 
oviposition, hatchmg, and incubation periods. The range of the 
averages for the months of August to November of the second year 
is 104.5 to 213.7 days, w^hereas the range for the same months of the 
first year is 56.2 to 167.4 days. The range of the averages for the 
rest of the months of the second year is 63.3 to 77.6 days, as com- 
pared with a range of 38.6 to 73.2 for the remaining months of tho 
first year. 

Longevity period. — Range of maximum and minimum longevity and average of maximum 

longevity. 



Month lots 
began to 
hatch. 



Ntim- 
bfir 
of 
lots. 



Range of 
minimum 
longevity 

periods." 



Range of 
maximum 
longevity 

l)eriods. 



Average 
of max- 
imum 
longe\"ity 
periods. 



Month lots 
began to 
hatch. 



Num- 


Range of 


Range of 


ber 


minimum 


maximum 


of 


longevity 


longevity 
periods. 


lots. 


periods. 




Days. 


Days. 


72 


(i to 60 


31 to 110 


355 


8toS7 


14 to 119 


ISO 


7 to 85 


25 to 139 


50 


9 to 48 


9 to lOG 


42 


7 to 47 


31 to 118 



Average 
of max- 
imum 
longev- 
ity 
periods. 



1908. 

August 

September 
October... 
November, 

1909. 
March 



Days. 
10 to 30 
6 to 02 
13 to 155 
51 to 146 



Days. 
99 to 192 
50 to 218 
80 to 249 
58 to 223 



Days. 
121.8 
104. 5 
21.3. 7 
149.9 



1909. 

April 

May 

June 

July 

August 



Days. 

75.: 
77. 
66. 
63.: 
64. 



ENTIRE TIME OF NONPARASITIC DEVELOPMENT. 



The entire time for each individual tick and its progeny, i. e., the 
time from dropping to the death of all the larvge, is given in the table 
in the Appendix. The longest entire time during the second year 
(297 days) was obtained m the case of ticks collected September 1, 
while the longest period for the first year (288 days) occurred in 
the case of ticks collected October 1. The shortest period for the 
second year was 96 days and for the first year 79 days, and both 
occurred in the case of ticks collected the first part of June. The 
averages for the first year increase month by month from June to a 
maximum for October, and then decrease for the remaining months, 
except that the averages for February and ]\Iarch are the same. 
The averages for the second year, given in the last column of the 
table below, do not increase to and decrease from the maximum 
without deviations, as do those for the first year. 



10 



BIOLOGY OF THE TEXAS-FEVEE TICK. 

Entire time of nonparasitic development. 



Date engorged 

females were 

collected. 


Number 

of 
engorged 
females. 


Range of 

entire-time 

periods. 


Average 

of 
periods. 


Date engorged 

females were 

collected. 


Number 

of 
engorged 
females. 


Range of 

entire-time 

periods. 


Average 

of 
periods. 


1908. 


4 
4 
3 

4 

4 


Days. 
143 to 254 
258 to 297 
271 to 280 
274 to 288 
257 to 268 


Days. 
206.5 
280 
279.3 

282 
264.8 


1909. 

January 1 

February 4 

March 1 




Days. 
202 to 253 
204 to 230 
lS5-to207 

139 to 164 

140 to 185 
96 to 127 

110 to 149 


Days. 


September 1 

October 1 


218.5 
198 3 






December 2 


May 1(?) 

June2(?) 

July 2 


156.5 
117 









NUMBER OF EGGS LAID AND PERCENTAGE HATCHED. 

During the second year the minimum number of eggs laid by a 
tick was 305 and the maximum 4,492. The average number of eggs 
laid by the various lots of ticks ranged from 1,885. to 4,262. The 
lowest percentage of eggs hatched was 3 per cent and the highest 
98 per cent. The percentage of eggs hatched in the case of ticks 
collected during December, January, and February ranged from 3 to 
60 per cent. For the first year the minimum number of eggs laid 
was 357 and the maximum number was 5,105, and the averages 
ranged from 1,811 to 4,089. The percentage of eggs hatched ranged 
from to 98 per cent. 

Egg laying and hatching — Total and average number of eggs laid and per cent hatched. 





Num- 


Date col- 


ber 


lected. 


of 




ticks. 


1908. 




August 5... 




September 1 




October 1 . . 




November 2 




December 2 





Number 

of eggs 

deposited. 


Average 
number 
of eggs. 


Per cent 
hatched. 


3,962 to 4,492 
2,797 to 3,654 
1,588 to 3,848 
2,215 to 3,329 
1,496 to 2,201 


4,262 
3,252 
2,768 
2,975 
1,885 


48 to 97 
92 to 98 
9 to 61 
52 to 71 
11 to 27 



Date col- 
lected. 



Num- 
ber 
of 

ticks. 



Number 

of eggs 

deposited. 



Average 
number 
of eggs. 



Per cent 
of eggs 
hatched. 



January!.. 4 305 to 3,723 2,615 

February 4. 4 1,993 to 2,970 2, 

March 1.... 4 l,3S0to3,361 2,352 

April 2 4 1,741 to 3,065 2,476 

May 11 4 3.181 to 4,178 3,679 

June 22 4 1,640 to 3,003 2,180 

July 2 4 2,214 to 3,710 

• Ticks were collected June 2, 3, 4, and 



3 to 60 
11 to 41 
61 to 93 
86 to 95 
69 to 93 
60 to 97 
96 to 98 



Ticks were collected May 1 and 2. 



COMPARISON OF RESULTS OF INDOOR AND OUTDOOR 
EXPERIMENTS. 



In the next table the dates when the first eggs hatched and when 
all the larv£e were dead in each month's experiments, indoors and 
outdoors,, are given for purposes of comparison. These dates are of 
much practical importance in eradication work when rotation methods 
are employed, since the dates when the first eggs hatched are those on 
which ticky cattle placed on tick-free land on dates corresponding 
to those on which the experiments were begun will be in danger of 
reinfestation, and the dates on which all larvae were dead are the 



COMPARISON" OF RESULTS. 



11 



dates on which pastures from which all animals have been removed 
will be free of ticks. 

Comparison of records of vertical tubes and field plots, Auburn, Ala., 1908-9. 



Vertical tubes. 



Date females were collected. 



Date first 

eggs 
hatched. 



Date aU 
larvae 
were 
dead. 



Field plots. 



Date first 
Date females were collected. \ eggs 
hatched. 



Date all 
larvae 
were 
dead. 



1908. 

Augusts 

September 1 

October 1 

November 2 

December 2 

1909. 

January 1 

February 4 

March 1 

April2 

May 1-2 

June 2-5 

July2 



Aug. 30 
Oct. 7 
Feb. 25 
Apr. 22 
May 11 



May 19 

May 21 

May 24 

May 28 

June 10 

July 2 

July 28 



Apr. 16 
June 25 
July 8 
Aug. 17 
Aug. 27 



Sept. 11 
Sept. 22 
Sept. 24 
Sept. 13 
Nov. 2 
Oct. 7 
Nov. 28 



August 5-C. . 
September 1. 
October 1 . . . 
November 2. 



1909. 



Aug. 31 
Nov. 23 
Apr. 19 
May 10 



January 1 ] May 21 

February 1-4 i May 20 

March 1-3 ...do.... 

April 2 May 26 

May 1-2 June 12 

June2-5 June 28 

July 1-2 July 26 



Apr. 3 

Mav 22 

June 23 

Do. 



Julv 30 
Aug. 6 
Aug. 25 
Sept. 11 

Do. 
Oct. 2 
Nov. 13 



In comparing the length of time required foj the first eggs to hatch 
in the indoor and outdoor experiments it was found that for all the 
months except March, April, June, and July the time was longer in 
the outdoor than in the indoor experiments, the differences ranging 
from 1 to 53 days, and for the above-mentioned months the time was 
shorter, the differences ranging from 1 to 4 days. The longer time 
obtained in the majorit}^ of the outdoor experiments may be due in 
part to unavoidable errors in observation because of the fact that it 
is frecj[uently difficult to determine with certainty when the fu"st eggs 
hatch, smce they are scattered and some may be hidden fi'om view. 
In the first year's experiments practically the same results were 
obtained. For two of the eight months for which comparisons could 
be made the time was the same in the indoor and outdoor experi- 
ments, and for the remaining months the time was longer in the out- 
door experiments, the differences ranging from 1 to 22 days. 

In view of the fact that in the two years' experiments the time to 
the hatching of the first eggs was longer in the outdoor experiments 
than in the corresponding indoor experiments in all except four 
instances, in which cases the differences were comparatively small, 
ranging from 1 to 4 days, it seems safe to assume that indoor experi- 
ments, if the temperature is maintamed uear that on the outside, 
will be safe to follow in practical work, provided a reasonable margin 
of safety be allowed to cover slight variations that might occur in 
the direction of a shorter time for hatclimg. 

In the second year's work, for all months the time required for all 
the larvae to die was longer in the mdoor than in the outdoor experi- 
ments, the differences ranging from 2 to 55 days, and the average 



12 BIOLOGY OF THE TEXAS-FEVEK TICK. 

difference being 28 days. In the first year's experiments similar 
results were obtained; in all but one case the periods were longer in 
the indoor than the outdoor experiments, the differences ranging 
from 5 to 42 days, the average difference being 21 days. It there- 
fore appears that the time obtained indoors, with incubation tubes of 
the type employed, as a rule will be three to four weeks longer than 
that occurring under natural conditions. This is what would be 
expected, since ticks in tubes are not exposed to the wand, and when 
kept indoors are not subjected to the sun, in consequence of wliich 
they will not suffer the loss of body fluids and nourishment that ticks 
living in the open will. In addition to this, it is likely that the 
humidity in the tubes as a rule is higher than that of the outside 
air, which would tend to prolong longevity of the larvae. It is be- 
lieved that in using tubes such as were employed, the supply of 
moisture should not be excessive, the sand simply being kept moist. 
Unless this is done it is likely that the life of the larvae may be pro- 
longed far beyond that occurring under natural conditions. Unduly 
long periods for the death of all larvae, obtained by using incubation 
tubes, are safe but uneconomical, requiring the farmer to forego the 
use of his land longer than is necessary. It is important that the 
periods be ample, but it is likewise important that they be no more 
than this, since rotation methods are inconvenient and expensive at 
best m the majority of instances. 

In comparmg the time required for all the larvae to die for corre- 
sponding months in the indoor experiments for the two years it was 
found that for all but one month the time was longer the second year, 
the differences ranging from 3 to 45 days. The average difference 
was 25 days. A similar comparison of the outdoor experiments for 
the two years showed that in every instance the time was longer the 
second year, the differences ranging from 2 to 36 days. The average 
difference was 17 days. 



APPENDIX. 



Individual records of ticks used in experiments. 



Num- 
ber of 
tick. 



Date col- 
lected. 



■Num- 
ber of 
e{;gs de- 
posited. 



Preovi- Oviposi- 
jwsition tion 
period, period. 



Hatch- 
ing 
period. 



Incubation 
period. 



Mini- 


Maxi- 




mum 


mum 


Entire 


lon- 


lon- 


time. 


gevity. 


gevity. 




Days. 


Days. 


Days. 


15 


116 


143 


12 


218 


254 


17 


141 


182 


6 


207 


247 


58 


249 


286 


15 


237 


279 


21 


902 


258 


13 


249 


297 


10 


ioo 


280 


10 


87 


271 




112 


278 


11 


107 


285 


6 


98 


274 


14 


110 


281 


18 


106 


288 


18 


100 


268 


8 


97 




19 


100 


268 


8 


87 


257 


16 


104 


243 


16 


113 


253 


21 


103 


242 


49 


64 


202 


17 


98 


204 


21 


114 


225 




111 


230 


28 


106 


215 


25 


116 


205 


14 


107 


196 


25 


97 


185 


25 


119 


207 


20 


106 


164 


23 


95 


154 


15 


101 


159 


11 


81 


139 


19 


118 


158 


17 


96 


140 


25 


100 


143 


14 


139 


185 


18 


80 


114 


20 


95 


127 


20 


62 


96 


9 


84 


117 


12 


118 


149 


13 


94 


125 


20 


81 


110 


' 


106 


134 



Per cent 
hatched. 



1908. 
Aug. 5 
..do, 
..do, 
..do, 
Sept. 1 



..do.. 

..do.. 

Oct. 

..do.. 

..do.. 

..do.. 

Nov. 

..do.. 

..do.. 

..do.. 

Dec. 

..do.. 

..do.. 

..do.. 



1909. 



Jan. 1 
...do.... 
...do.... 
...do.... 

Feb. 4 
...do.... 
...do.... 
...do.... 

Mar. 1 
...do.... 
...do.... 
...do.... 

Apr. 2 
...do.... 
...do.... 
...do... 

May 1 
...do.... 
...do.... 
...do.... 

June 22 
...do.... 
...do.... 
...do.... 

July 2 
...do.... 
...do.... 
...do.... 



4,492 
3,962 
4,489 
4,104 
3,654 
3,604 
2,951 
2,797 
1,588 
3,848 
2,730 
2,906, 
3,187 
3,329 
3,167 
2,215 
1,858 
1,985 
2,201 
1,496 



3,723 
3,460 
2,970 
305 
2,601 
2,970 
2.706 
1,993 
2,994 
1,674 
3,361 
1,380 
2,607 
3,065 
1,741 
2,491 
4,178 
4,040 
3,181 
3,296 
2,311 
3,003 
1,765 
1,640 
3,452 
3,710 
2,214 
2,416 



Days. 
3 

4 



Days. 
15 
13 
15 
14 
16 
IS 
9 
16 
13 
35 
20 
33 
63 
56 
58 
61 
31 
35 



Days 



Days. 

20 to 36 

20 to 30 

21 to 34 
21 to 30 
32 to 73 
36 to 75 
31 to 71 
34 to 70 



141 to 176 
151 to 174 
146 to 174 

151 to 170 

152 to 168 
151 to 170 
143 to 169 

114 to 138 
103 to 142 
110 to 144 

115 to 139 



61 to 119 
73 to 120 
94 to 121 
111 to 117 

53 to 87 

68 to 97 

49 to 87 

70 to 90 

45 to 81 

57 to 84 

44 to 77 

55 to 77 

36 10 49 

39 to 50 

39 to 51 

35 to 48 

26 to 39 

27 to 37 

28 to 36 
27 to 41 
18 to 27 

21 to 27 

22 to 29 

21 to 27 
24 to 27 

22 to 27 

23 to 29 
23 to 28 



1 Ticks were collected May 1 and 2. 



2 Ticks were collected June 2, 



4, and 5. 

13 



O 



>v 



